CTM is a program for estimation of Continuous Time Multi-State Multi-Spell Models embodying major advancesin survival analysis. It handles competing risks, multiple spell transitions (birth spacing intervals, repeated episodes of remission), multi-statedata and parametric and nonparametric unobserved heterogeneity. This difficult to use mainframe-only program will be converted to more accessible fault tolerant and user assisting SYSTAT and SAS versions. Comprehensive manuals with examples from biomedical and social science research, with detailed discussion of methods, rationale, model selection, and diagnostics will be written. Recent developments for semi-parametric modeling will be incorporated and revised computational algorithms will substantially improve performance for the most common models. The program will be developed principally on the HP-9000/850 (Unix), and IBM-PC, and will be ported to IBM mainframe (CMS and MVS), VAX (VMS and UNIX), and SUN platforms using libraries previously developed. The resulting products will provide advanced new tools for epidemiology, clinical trial evaluation, and health science and social science research generally.